1. Technical Field
The present invention relates to a printing control device and a printing control method.
2. Related Art
Ink jet printers, for example, dots are formed on print substrates by relatively moving recording heads having nozzle lines in which a plurality of nozzles are arranged in predetermined nozzle line directions relative to the print substrates in relative movement directions intersecting the nozzle arrangement directions and ejecting ink droplets (liquid droplets) from the nozzles according to nozzle data that indicates presence or absence of an ink dot for each pixel. Ink jet printers in which main scanning and sub-scanning are repeated include, for example, serial printers in which high-speed printing such as band printing is performed and serial printers in which pseudo-band printing is performed. Here, the band printing is a printing scheme of forming all of the dots of a band having a length corresponding to a one-time feed amount (also referred to as a transport amount) of a print substrate in a sub-scanning direction through one-time main scanning. The pseudo-band printing is a printing scheme of forming all of the dots of a band, which is a unit in which all of the dots are formed in a sub-scanning direction, through M-time main scanning (where M is an integer equal to or greater than 2). Sub-scanning between main scanning at the time of formation of dots of equal bands is a feed amount corresponding to 1/M of a pitch of nozzles in a sub-scanning direction.
There is a possibility of banding (stripes formed in a main scanning direction) occurring in boundaries of bands due to a transport error of a print substrate or a landing error of dots between the bands. To reduce the banding, partial overlap printing is performed in which print regions, where print images are formed at the time of main scanning performed before and after sub-scanning of a distance longer than a pitch of nozzles in a sub-scanning direction, are partially overlapped. In the partial overlap printing, recording of the overlapped overlap regions is divided into main scanning before the sub-scanning and main scanning after the sub-scanning.
JP-A-2003-53957 (particularly, summary and claims 2 to 4) discloses an ink jet recording apparatus that is capable of adjusting a distance interval between a recording head and a recording medium by rotation of an eccentric shaft. The ink jet recording apparatus calculates a value of (10×v2)/(d×r) by adding an ink ejection speed v2 [mm/s] and a record density r [dot/mm] of the recording head and suppresses a scanning speed v1 of the recording head so that v1 (10×v2)/(d×r) is satisfied.
Of requests for improving a printing speed, it has turned out that a landing range of an ink droplet is extended in a sub-scanning direction when the speed of main scanning of the recording head is increased. When the landing range is extended, for example, at the time of band printing, mutually adjacent bands are partially overlapped and dark stripes in the main scanning direction occur in some cases. Such dark stripes occur in some cases irrespective of whether overlap printing is performed, and thus pseudo-band printing or the like occurs in some cases.
The foregoing problems similarly occur in various apparatuses.